CTC 261 Hydraulics Introduction

1
CTC 261 HydraulicsIntroduction
Its no coincidence that a meter---not
one-millionth of a meter and not ten thousand
metersis, roughly speaking, the size of a
person. Its about twice the size of a baby and
half the size of a fully grown man. It would be
rather strange to find that the basic unit we use
for common measurements was one-hundredth the
size of the Milky Way or the length of an ants
leg. Lisa Randall, Professor of Theoretical
Physics, Harvard Knocking on Heavens Door, 2011,
ISBN 978-0-06-172372-8

2
Objectives

• Know the class requirements
• Know the definition of hydraulics
• Be familiar with common fluid properties

3
Class Requirements

• On-Web www.sunyit.edu/barans
• Syllabus
• Schedule
• Lectures/Assignments
• Grades
• Academic Integrity Policy (page 49)

4
Fluid Mechanics

• Science that deals with the action of forces on
  fluids

5
Fluid

• Continuously deforms

6
Hydrodynamics vs Gas Dynamics

• Noncompressible
• No change in density
• Mathematically easier

• Compressible
• Significant density change
• Mathematically more difficult

7
Hydraulics

• An extension of fluid mechanics in which many
  empirical relationships are applied and
  simplifying assumptions made to achieve practical
  engineering solutions

8
Significance in Civil Engineering

• Water systems
• Wastewater systems
• Open channel flow
• Dams
• Erosion Control
• Hydraulic Structures
• Bridges
• Culverts
• Ditches
• Retaining structures

9
History
5,000 years ago Irrigation Egypt
2,500 BC Bamboo pipes China
200 BC Lead/Bronze Pipes Rome
 Romans built many stone aqueducts, many of which
are still standing. Utilization of theory began
after 1850. Before that, designs were
rule-of-thumb.
10
Loss of Culvert due to flooding on I-88 June
28,2006 Two truckers were killed
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Next Lecture

• Fluid Properties

15
Common Fluid Properties
SI USC/FPS
Temperature K (273C) F
Mass Kg Slug
Length Meter (m) Foot (ft)
Time Second (sec) Second (sec)
Force N (kg-m/sec2) Lb (slug-ft/sec2)
Pressure Pascal (N/m2) Psi
16
Other common units
Gravity Constant 9.81 m/sec2 32.2 ft/sec2
Specific Weight, Water (force per unit volume) 9.81 kN/m3 (0-10 deg C) 62.4 /ft3 (40-60 deg F)
Mass Density, Water (mass per unit volume) 1000 kg/m3 (0-10 deg C) 1.94 slugs/ft3 (40-70 deg F)
Specific Gravity Specific weight of a liquid / specific weight of water (at some std. temp.) Specific weight of a liquid / specific weight of water (at some std. temp.)
17
Water Properties

• Function of temperature/pressure
• See Angel folder for the water properties to be
  used in this class

18
Fluid Properties - Thermodynamics

• Specific Heat
• Specific Internal Energy
• Specific Enthalpy

19
Elasticity of Water

• Amount of deformation for a given pressure change
  (bulk modulus of elasticity)
• Water is essentially incompressible (although it
  is approximately 100 times more compressible than
  steel)
• See http//hyperphysics.phy-astr.gsu.edu/hbase/per
  mot3.html for equation relating to pressure and
  volume change

20
Water Elasticity

• What pressure is required to reduce the volume of
  water by 0.5 (.005)?
• Using equation the pressure required is
  approximately 1,600 psi
• (3/4 of a ton per square inch)

21
Viscosity

• Related to resistance of shear forces
• Newtonian fluid linear relationship between
  shear stress and the rate of deformation (gases
  and most liquids)
• Non-Newtonian fluid nonlinear relationship
  (thick, long-chained hydrocarbons)
• High Viscosity honey, tar
• Low Viscosity water, air

22
Viscosity

• For a Newtonian fluid
• Shear stress(F/A)ViscosityShear Rate
• Shear rate (velocity gradient) is the rate at
  which one layer moves relative to an adjacent
  layer (change in velocity divided by change in
  distance)

23
http//www.technet.pnl.gov/sensors/macro/projects/
images/macro81lg.gif
24
Non-NewtonianNewtonianViscosity

• http//antoine.frostburg.edu/chem/senese/101/liqui
  ds/faq/non-newtonian.shtml

25
Non-Newtonian Fluid

• http//www.youtube.com/watch?vf2XQ97XHjVw
• http//www.youtube.com/watch?vcuzn8wh8Fysfeature
  related

26
Viscosity-Units

• Dynamic (absolute)
• Units are N-sec/m2 or lb-sec/ft2
• Kinematic
• Dynamic viscosity divided by mass density
• Units are m2/sec or ft2/sec

27
Viscosity

• A Newtonian fluid is in the clearance between a
  shaft and a concentric sleeve. When a force of
  600N is applied to the sleeve parallel to the
  shaft, the sleeve attains a speed of 1 m/s. If a
  1500-N force is applied what speed will the
  sleeve attain?
• Speed would be proportional to the force since
  the area, viscosity and distance between sleeve
  and shaft are constant. Speed 2.5 m/sec

28
Next Lecture

• Fluid Statics
• Absolute/gage pressure
• Hydrostatic pressure on horizontal surfaces
• Converting pressure to pressure head
• Defining center of pressure
• Hydrostatic pressure on vertical surfaces